Gage.



R. CONRAD.

GAGE.

APPLICATION FILED JUNE 26.1913.

Patented May 8, 1917.

ROBERT CONRAD, 01E BERLIN, GERNLANY.

GAGE.

To all whom "525 in my concern Be it known that l, Ronnnr CONRAD, a sub ject of the Emperor of Germany, and a resident of Berlin, Germany, have invent-ed certain new and useful Improvements in Gages, of which the following is a specification.

This invention relates to non-adjustable gages for accurately determining whether or not holes, cavities or spaces between members are of the desired size, and this application is a continuation of my prior appli cation, Serial No. 4439,5359, filed December 29th, 1908, as to most of the subject-matter thereof. To determine the size of a hole, opening, or space, cylinders of known diametcr or solid bodies having opposite parallel surfaces spaced a predetermined distance apart, have heretofore be-o. used, as for instance plug gages or slide gages, snap gages, and so on, but the construction of such cylinders or other such bodies with an exactness of 1/500 to 1/1000 of a millimeter is comparat'vely ditlicult, and consequently e pensivc. A. primary object of my invention is to provide instruments for this purpose which can be made much cheaper, but with the same accuracy or even greater accuracy than those heretofore known.

As distinguished from the known instruments mentioned above, I make the measuring portions of my improved gages from spheres or bodies presenting spherical surfaces. It is possible to produce steel balls on a large scale by the use of ball grinding machines, at small cost and with an accuracy of dimension which far exceeds 1/1000 part of a millimeter, and moreover in graduations as small as desired. In addition, my instruments are more convenient to use, measurements may be made with more certainty than heretofore, and neither the parts which are measured nor the gages are likely to be scratched, worn. or damaged, as much as formerly. This is due to the fact that the spheres can not be placed edgewise and are; of the same dimension through every diameter. They make possible finer measurements, are of unprecedented exactness, are capable of receiving the hardest polished surfaces, do not become distorted nor bent in use, possess longer life and are cheaper to manufacture and more easily used than other gages heretofore known. They do not distort themselves after a time by reason of any hardening strains as any strains which are set up by the hardening process Specification of Letters Patent.

Application filed June 26, 1913.

Patented May 8, rear.

Serial No. 775,842.

will neutralize each other due to the spherical form. As difierent surfaces come into play upon successive utilization of the in strument the wear is very materially less. The spherical surface absolutely prevents the instrument from getting cocked or set at an angle in the work and thus postively prevents the obtaining of erroneous conclusions by the. careless use of the instrument.

To use ordinary calipers for measuring, the mechanic must be very skilful as the angle at which the instrument is introduced is very important, whereas in my improved construction, it is entirely immaterial. The workman upon introducing the caliper into the outer part of the boring can do so witl out care as to the angle with the axis of the bore, and any change in, this angle only brings another and equally accurate surface into contact with the body which is being measured. Furthermore, the curved surface of the sphere automatically guides it into the hole. On shoving the caliper farther into the bore the axis of the handle becomes more nearly parallel with the bore. and thus the wear is automatically distributed oyer a large portion of the surface of the ball. This adds greatly to the life of the instrument. The outer edge of a cylindrical caliper is almost invariably more or less damaged even though the instrument receive average good care. This damage is unavoidable, increases the ar a in measuring and tends toward obliquity. Faults of this order can not come into consideration with the ball caliper, principally because of the much greater hardness and the spherical shape. Cylindrical calipers must be made singly and although the balls which are used for measuring purposes naturally requ re great care in their manufacture. yet it is possible by the use of entirely different methods to turn out ball calipers at very much less cost. Faults such as the wearing off of the tips of the calipers are impossible in my construction.

My improved caliper includes a ball preferably of hardened steel, and a handle or holder connected thereto in such a manner that diametrically opposite portions of the ball are exposed. The character of the holder and the method of securing the same to the sphere may be varied according to the use for which the instrument is designed. If the instrument is to be used in determining the accuracy of a round opening or cavity the holder should be so secured to the ball that the periphery of the ball in a plane at right angles to the general direction of the handle is exposed at the maximum diameter and-for appreciable distances upon each side thereof. Thus the ball may be inserted in the opening with the handle substantially in alinement with or at a slight angle to the axis of the opening. If the instrument is to be used for determining the distance between two parallel surfaces, it is only essential that diametrically opposite surface portions of the ball are exposed. These are preferably upon opposite sides of the general direction of the length of the handle.

Reference is to be had to the accompanying drawings in which I have illustrated various different ways in which the handle may be secured to the ball to facilitate the use of the latter as the measuring portion of the instrument. It is evident that other forms might be designed and that my invention in its broad aspect is not limited to any one of the specific forms shown.

In these drawings Figure 1 is a plan view of a simple form of instrument with separate balls secured to opposite ends of a handle member.

Fig. 2 is a detail view showing a simple handle fastening means for tubular handles;

Fig. 3 is a plan view partly in section showing another fastening means;

Fig. 4: is a plan view of a construction in which the ball is attached by a bolt and nut;

Figs. 5, 6 and 7 show various balls provided with holes and adapted for use with the holder shown in Fig. 1;

Figs. 8 and 9 are plan view and section respectively, of a construction in which the handle is formed of sheet metal strips and exposing only opposite sides of the balls;

Figs. 10 and 11 are section and plan views respectively, of a construction in which a larger number of balls is held;

Fig. 12 is a plan View of a gage having the handle soldered, brazed or otherwise permanently secured to balls, the opposite sides of which are cut away leaving peripheral spherical. surfaces;

Figs. 18 and 14 are plan view and section respectively of a further means which may be employed for securing a handle to a ball section of the character shown in Fig. 12; and

Fig. 15 is a sectional View of a construction having a handle the length of which may constitute a gage.

Referring particularly to Fig. 1 it will be noted that my improved device involves a small sphere or hardened steel ball a of the desired diameter within the required limits of exactness. This ball or sphere may be flattened at one part for the reception of an inscription indicating its size. For convenience in handling, the ball is provided with a holder or handle '5 which may be se cured to it in any suitable manner, as for instance magnetically or by solder or readily fusible metals or by being brazed thereon. T have shown the handle provided with separate balls at each end so that the instrument may be used as a limit gage, that is one ball is of a diameter slightly less than the desired dimension of the finished part and the other slightly greater. Between these limits the completed work must lie. If desired there may be no relationship between the diameters of the balls at opposite ends of a handle, the two being used for different parts of the work.

Tnstead of securing the ball to the holder by magnetism, brazing or soldering, I may employ the holder 0, shown in Fig. 2. This holder com arises merely a Jiece of metal tubing of smaller diameter than the ball a and secured to the latter by cutting an annular bead or groove (Z in the ball at one side of a diameter thereof. The end of the tube forming the handle may be slightly expanded and forced over the smaller section of the sphere until it abuts against the larger section. This smaller section constitutes a projection from the larger section and may be of any suitable diameter materially smaller than the diameter of the ball. The proper diameter will depend upon the diameter of the handle employed. The metal of the tube may then be headed, spun or rolled inwardly into the groove of the ball and thus form a permanent rigid connection between the two. I have only shown one end of the tube but it is evident that the opposite end may or may not be provided with a separate ball secured in the same or some other manner.

In Fig. 3 T have illustrated a slightly different means for securing a tubular handle 0 to the ball a Here again I cut an annular groove in the ball but the sides of the grooves may be at right angles to each other, one side being cylindrical and the other lying in a flat plane. The end of the tubular iandle may be split seas to permit it to be stretched over the cylinder portion of the ball at the groove and a collar 6 of the proper size may then be driven enclwise of the handle to firmly bind the handle to the ball. The parts may then be brazed or soldered if desired, although this is not ordinarily necessar The ball may be secured to the handle as shown in Fig. 4. Here the ball a is ground away at two opposite places so that a hole may be bored therethrough for receiving a rod 7 constituting an extension of the handle The end of the rod f may be threaded and the ball may be detachably secured in place by a suitable nut h. To facilitate the boring of the hole through the ball, the latter is preferably not hardened to as great a depth as i the ball shown in Fig. 1. This permits one handle to be used for a large number of balls of different sizes.

Balls having c-vities, holes, flat places, and the like may be produced according to my invention, in the following manner: Preferably before the ball is hardened one hole as shown in Fig. 5, or several holes as shown in the ball a in Fig. 6, are drilled in it. The holes are then closed by plugs and the balls together with the plugs are then finished. The plugs are subsequently removed and the desired handle or holder secured in one of the holes. When several holes are provided as shown in Fig. 6, it is possible to attach a holder consecutively in various holes so that different parts of the surface of the ball can be consecutively used for measuring and the length of life of the tool can be correspondingly increased.

T he ball may also be made as indicated in 7 in which the ball is made up of three separate sections, 2", j and 7c, the planes of division therebetween being parallel and the sections held together by a plug through the hole shown in dotted lines. After the ball is made spherical, the outer sections or parts 2' and in may be removed leaving the portion with flat parallel sides. Two such ball sections may be soldered, brazed or otherwise rigidly secured to a handle Z as shown in Fig. 12, and used as substitutes for flat limit gages heretofore known. Such a ball section may be connected to a handle on as shown in Fig. This handle has two forks or spaced arms 0 between which the ball section is mounted on a pin a, the ball section being free to revolve between these arms about the pin as an axis. Such an instrument may be used for the measurement of successive points between parallel surfaces and without the wear which ordinarily accompanies the sliding of a gage along over the surfaces being measured. If it is desired to hold the ball sections from rotation this may be accomplished by tightening a set screw 79 in one of the arms and against the side of the ball section.

Instead of cutting or otherwise deforming the ball to facilitate the attachment of the handle thereto, 1 may form the handle substantially as shown in Figs. 8 and 9. Here the handle is made up of two strips of sheet metal r-r perforated and cupped at their ends and secured together by rivets or in any other suitable manner. lhe balls supported as shown in Figs. 1, 2, 3 and l have the major portion of their peripheral surface exposed and particularly the circumferential portion in a plane at right angles to the general direction of the handle, thus the instrument may be inserted endwise into a hole to determine the diameter thereof, or it may be used for determining the distance between two parallel surfaces. The construction shown in Figs. 8 and 9 is not adapted for determining the diameter of round holes, but only for determining the distance between two parallel or siiibstantially parallel surfaces. It will be noted that the portions of the surface of the sphere are diametrically opposite to each other, but no annular or peripheral portion is exposed as in Figs. 1, 2, 3 and i.

In Figs. 10 and 11, I have shown an instrument in which several gages or balls at of different diameters are all held in a single holder formed of two circular plates ss spaced apart and held in position by a central rivet t. One of the plates may be marked adjacent each ball with the diameter of the latter, and the instrument may be used for effecting several limit measure ments with the aid of a single instrument.

In my prior application above referred to I have disclosed a large number of different forms in which balls may be employed as the determinative measuring parts and have claimed specifically a type of gage one form of which is illustrated in Figjlo of the present application. This gage includes a tubular holder to with a shorter tube '0 therein to hold a series of balls to of different diameters. l have illustrated the outer tube as being connected to a ball 0; in substantially the same manner as shown in Fig. 2 so that the tube a may serve as a handle for the ball gage a and the entire devic e may be used as a gage for determining distance equal to the distance between the extremes of the ball a and the opposite terminal ball to which projects through an opening in a cap 00.

Having thus described my invention, what I claim as new and desire to protect by Letters-Patent, is:

1. A. gage comprising a one-piece gaging member in the form of a spherical steel ball presenting a polished, hardened peripheral surface with all diameters constituting the determinative measuring distance and having a portion at one side of said peripheral surface cut away to leave a non-spherical surface, and a handle secured to said member at said non-spherical surface and of smaller diameter than said member, whereby said member may enter the bore or interior to be gaged and insure accurate gaging irrespective of wide variation in the angle of the handle in respect to said bore or interior.

2. A gage comprising a steel spherical ball having a hardened polished surface and a handle secured thereto, said handle being of smaller diameter than said ball at the point of attachment whereby said ball is adapted to enter the bore or interior to be gaged irrespective of wide variations in the angle of the handle in respect to the bore,

combination a one-piece gaging element in the form of a steel ball having a hardened spherical surface, said member being adapted to enter the bore or interior to be gaged and afford all the gaging contacts therefor, and a separate handle, said gage piece being provided with a projecting portion and said handle at one end serving to receive and retain said projection.

5. A plug or bore gage comprising in combination a one-piece gaging element adapted to enter the bore or interior to be gaged and afford all the gaging contacts therefor, and a separate handle, said gage piece provided with a projecting portion and said handle at one end serving to receive and retain said projection, and a locking ring encircling said end portion and retaining the latter in engagement with said projection.

6. Agage comprising a spherical member adapted to enter the bore or interior to be gaged and presenting a hard polished surface and having its diameter constituting the determinative measuring part, said member having an annular groove parallel to a great circle and dividing the member into a larger and smaller portion, and a.

handle having an opening at one end receiving the smaller portion of said member and said handle terminating in said groove.

7. A gage for use in insuring the formation of a series of openings of uniform size within a predetermined permissible limit of variation, including two rigidly connected spherical gaging balls, each presenting oppositely disposed polished hardened spherical surface-portions, and the diameter of one ball constituting a maximum limit gage and the diameter of the other constituting a minimum limit gage.

8. A gage for use in insuring the formation of a series of openings of uniform size including two spherical gaging balls each presenting oppositely-disposed, polished, hardened, spherical surface-portions, said surface-portions of each ball having a common center of curvature and the difference between the diameters of said balls being accurately predetermined and constituting the maximum permissible variation in the work for which the gage is designed.

9. A gage including two steel balls each presenting oppositely-disposed polished harcloned spherical surface-portions and a handle connecting'them, said surface-portions of each ball having a common center of curvature, said balls being of different diameters.

10. A measuring apparatus comprising two balls constituting maximum and minimum limit gages, and handle member connecting the same.

11. A measuring apparatus comprising two balls constituting maximum and minimum limit gages, and a handle member connecting the same and of smaller diameter than either of said balls.

12. A measuring apparatus including a member presenting a spherical surface, the diameter of which constitutes the determinative measuring distance, and said member presenting a substantially cylindrical portion, and a. tubular sheet metal handle for said member and receiving said cylindrical portion in the open end thereof.

Signed at Berlin, Germany, this thirtyfirst day of May, A. D. 1913.

ROBERT CONRAD.

Witnesses:

HENRY HAsPnR, WOLDEMAR HAUPT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

